Spark plug containing an intensifying gap



1933- J. D. CURTIS SPARK PLUG CONTAINING AN INTENSIFYING GAP Filed April 14, 1951 FIG.1

F l G. 5

JAMES D. cuuls INVENTOR BY W as ATTORNEY Patented Aug. 15, 1933 SPARK PLUG CONTAINING AN INTENSIFY- v ING GAP James D. Curtis, (lollingswood, N. J.

Application April 14, 1931. Serial No. 529,899

3 Claims.

The subject of my invention is aspark plug for internal combustion engines. In order to intensify the spark between the electrodes or points of the plug I provide the plug with an intensifying gap in it.

The novel design of intensifying gap which I employ for this purpose is a feature of my invention. This intensifying gap is connected to the terminal post of the spark plug and to the inner electrode by the use of metallic wool, which is also a feature of my invention. V

Since my spark plug is intended for use in internal combustion engines which are designed to use higher compression ratios, it is necessary to provide gas-tight joints between the parts comprising the spark plug. The novel means which I employ to provide such gas-tight joints are a novel feature of my invention.

For a further exposition of my invention reference may be had. to the annexed drawing and I specification at the end whereof my invention will be specifically pointed out and claimed.

In the drawing, Figure 1 is a vertical cross section through my 25, device.

Figure 2 is a side elevation of my device. Figure 3 is a horizontal cross section on line 33 of Figure 1.

Figure 4 is a horizontal cross section on line 30. 4-4 of Figure 1.

Figure 5 is a detailed view in elevation showing the hollow spindle.

Figure 6 is a plan view of the spindle shown in Figure 5.

In the embodiment of my invention chosen for illustration in the drawing, my novel spark plug is shown as consisting of a porcelain insulator 1 having a hollow chamber therein. In one end of insulator 1 is mounted a metallic terminal 2 having a screw threaded terminal post 3 extending therefrom onto which binding nut 27 is threaded which has slot 4 therein to receive a clip or other connection from the electrical wiring.

In the hollow in insulator 1 there is located an intensifying gap consisting of the body or block of insulating material 7 which has an axial hole therein in the axial dimension of the spark plug. Passing laterally through the body 7 are a plurality of wires 6 whose ends may conveniently be bent parallel to the sides of the body 7. The ends of the lowest Wire 6 are bent over the lower face of the body 7. Beneath the intensifying gap and within the hollow in insulator 1 there is located a lock nut 8 which is conveniently attached to insulator 1 by means of screw threads. Through the center of lock' nut 8 passes the inner electrode 10 which is conveniently attached to the lock nut 8 by means of screw threads. Electrical connection is pro.- vided between the terminal 2 and thefupper wire 6 and between the lowest wirefi and inner electrode 10 by means of metallic wool 5 for which purpose I prefer to employ an alloy of suitable metals. Beneath nut 8 there is located a lock washer 9. f j Surrounding inner electrode 10 I provide a layer of insulating material12 which is conveniently composed of a winding of mica. Surrounding the upper end of layer 12 an additional insulation is provided by a pile of micafwas'hers 11 compressed together to form a solid element as shown in thedrawing. surface of insulator 1 is a mica packing or washer 25. Adjacent its lower end insulator 1 v Surrounding the end 1 carries a circumferential groove 13 which is conveniently made semicircular in vertical cross section. Surrounding the lower end of insulator, 1 and packing 25 and likewise surrouding but spaced from the inner electrode 10 I provide a gland 15 which is suitably counter-bored. Gland a 15 is attached to insulator 1 by means of a pin 14 which passes through the upper part of the gland and through a portion of the groove13.

Pin 14 may conveniently be made with a slot in its head to receive a screw driver as is best seen in Figure 2. Surrounding the central part of electrode 10 and the layer 12 of insulation thereon I provide a hollow spindle 18 shown in detail I i r in Figure 5. Spindle 18 is provided at itsupper and lower ends with flanges having notches 24 which extend therethrough and into the central portion of the spindle for a short distance. Surrounding spindle 18 I provide a plurality of' chuck sleeve casings 17 which are semi-cylindrical in shape as best seen in Fig. 3. These casings 17 may, as shown, have, at the upper and lower ends of their inner surfaces, shouldered notches to receive the flanges on spindle .18

therein. On their outer surfaces casings 1'7 have flared surfaces cooperating with the'flaring inner surface of the lower part of gland 15. At their 1 lower end casings 17 have additional flaring surfaces 19 which. are preferably accurately ground for the purpose hereinafter described. Between the casings l7 and fitting into the notches 24 in spindle 18 I may, if desired, provide keys 30 which serve to guide and align the casings 17 during their clamping action. Adja cent but spaced from its lower end electrode 10 is provided with an insulator 26 surrounding the layer of insulation 12 and consisting of a pile 'of mica washers which are compressed together to form a single element as shown in the drawing. At its lower end electrode is conveniently provided with a point 21 which is preferably made of metallic alloy containing molybdenum.

Surrounding the lower part of the spark plug I provide a shell 16 which is made with itsupper threaded portion shell 16 is provided with a flar- V ingsurface which is preferably ground to cooperate with the ground flaring surfaces 19 on casings 1'7. At its lower end shell 16 is provided with screw threads 26 and with an outlet opening 23 which servesto form a cooling chamber. Opposite point 21 oninnerelectrode 10 shell 16 is provided with a ground wire 22 which serves as a spark point and which is preferably made of an alloy containing molybdenum. V As is pointed out above it is important in spark plugs for use in'high compresion engines to'provide agas-tight joint. This is accomplished in my device by assembling'casing 1? either directly 'on spindle 18 or' in contact with spindle 18 with keys between the casings 1'7. Shell 16 is then attachedto the screw threads on gland 15'andthe shell screwed up on the gland until the flaring surfaces on shell 16 come into contact with the flaring surfaces on casings 17. Further screwing of shell 16 onto gland 15 causes the flaring surfaces betweenshell 16 and casings 1'1, thesebeing the flaring surfaces at 19,to slide and therefore to force the flaring surfaces between gland 15 and casings 17 into close gas-tight connection.

It will also be seen that by means of my novel intensifying gap, composed of elements 6 and '7, an increased spark is obtained between'the points 21 and 22..

It will also be seen that by means of'the me-- tallic wool 5' the current is more readily conducted to the condenser and then conducted from thence to the electrode 10.

I do not intend to be limited in the practice of my invention save as the scope of the prior art and of the attached claims may require.

1 claim:

1. A spark intensifying gapfor use with spark plugs including in. combination an insulating block having a hole therein, and a plurality of cylindrical bodies mounted in said insulating block and having exposedends.

' 2. A spark intensifying gap for use with spark plugs including in combination a block of insulating material having an axial hole therein, and a plurality of wires mounted in said block soas to be insulated from each other and having ends extending laterally fromthe sides of said block, the ends of one of said wires being bent about one end of said block. Y 7

'SL'A spark intensifying'gap for use in spark plugs including in combination a block of insulat ping material having an axial hole therein; and

a plurality of wires mounted in said block so as to be insulated from each otherand extending laterally through said block and h'aving'exposed ends. Q

JAMES D. CURTlS. 9 

